Process of burning fuel.



PATENTED NOV. 20, 1906.

J. M. SCHUTZ. PROCESS OF BURNING FUEL.

APPLICATION FILED JAN.26.1903.-

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UNITED STATES PATENT OFFICE.

JOSEPH M. SGHUTZ, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR OF ONE- FOURTH TOCHARLES G. HAWLEY.

PROCESS OF BURNING FUEL.

Specification of Letters Patent.

Patented Nov. 20, 1906.

Application filed January 26, 1903. Satin-1H0- 140,560.

To all whom it mag concern:

Be it known that I, Josnrn M. SoHU'rz, of the city. of Minneapolis,county of Hennepin, and State of Minnesota, have invented new and usefulImprovements in Processes. of Burning.Fuel, of which the following is aspecification.

This invention relates to the production of heat from fuel, andparticularly from broken or pulverized fuel.

Hitlierto attempts have been made to burn pulverized fuel, in some casesalone and in others auxiliary to the ordinary grate-fire; but in allsuch cases that have come to my knowledge it has been necessary to dryand reduce the fuel to a uniform impalpable powder, and the cost of thuspreparing the fuel has been prohibitive for ordinary use, so that evenfor experimental efiorts success has not been claimed, and but littleprogress has been made in the reduction of the art to commercialrequirements and uses.

The object of my invention is to make use of all fuel products that maybereduced to a comparatively fine condition, but not necessarilypulverulent, and to consume the fuel with such degree of erfection as toextract a maximum of heat t erefrom and also avoid the loss ofcombustible gases and the escape of smoke.

My invention consists in the improved pro 0- ess of burnin 'fuel, ashereinafter generally and specifical y set forth, whereby a maximum ofheat may be obtained from solid or fluid fuel in a broken or dividedstate, its nec essary condition bein governed by the size of theapparatus emp oyed and the velocity of the air-current used in carryingout my process.

. The invention will be more readily understood by reference to theaccompanying drawings, forming a part of this specification, and inwhich Figure 1 is a sectional and diagrammatic view of the apparatusthat I prefer to employ for the carrying out of my process. Fig. 2 is asectional detail of the tWyer-head of the fuel-burner on the line X ofFig. 1.

. I do not in this application make claim for the novel construction ofthe apparatus shown and hereinafter described, for thereason that thesame constitutes the subject-' matter of a companionapplication-executed of even date herewith-to Wit, Serial No.

104,561, filed January 26, 1903. Moreover, my improved process is notnecessarily confined in its practice to the use'of any specific form orconstruction of apparatus beyond the general devices andfeaturesrequired for performing the several steps of the process.

The term fuel as employed in this specification is intended to embracenot only coal of the better qualities, but also the poorer kinds ofbituminous coal, such as li nite, and the waste or fine parts of allcoals, inown as screenings. The term also includes gases, oils,Wood-shavings, and sawdust,combusti ble mixtures, and garbage productsin suitable condition for combustionin other Words, any fuel substanceor compound that is capable of being shattered, crushed, pulverized, orseparated into particles small enough for easy conveyance or which isalready in such condition.

The term pulverized as used herein is intended to describe or definethat broken state of the fuel, Whatever the kind, that will admit ofcarrying, distributing, or feeding of the fuel by an air or gas blast ofa velocity suited to the requirements of the given furnace lant or byconveyers, elevators, and

132111.611]: e, as distinguished from large lump- As will be madeevident hereinafter, it is unnecessary and even objectionable to reducethe fuel to substantial .impalpability,

for the reason that in my device combustion is induced notspontaneously, but rather by a series of steps or stages, causing,first, the rapid decomposition of the fuel; second, the ignition of theresulting gases, and, third, a thorough admixture of the burning gaseswith sufficient air to produce complete or perfect combustion.

My process may be broadly defined as comprising the following steps, towit: forcibly forming a rapidly-moving and rotating column of air andadding fuel thereto, confining the columnand fuel particles to spiralpaths, thereby causing the projection of the 'fuel particles and gasesaway from the axis of the column, and applying heat to the productsduring the transit of said spiral path, thereby column aforesaid, andthereby preventing the escape of unconsumed products from said spiralpath until the same are heatedto the point of combustion, and, further,the

rocess consists in supplying airor gas to urning gases through themedium .of said vortex. f

A further step consists in rotating the medium for continuously storingthe heat and in which the gases are momentarily confined, as abovedescribed.

The process also includes other and intermediate or auxiliary steps, allof which will be better understood from the description of the pparatusshown in the drawings above referred to. I

In said drawings I have shown a burner constructed in accordance withthe requirements of my process and as applied to a boiler-furnace,whereof A is the combustion- .chamber, and B the ash-pit, which latteris provided with a suitable ash-discharge. (Not shown.)

C is the rotary burner, whereof D is the feeding-head.

E is thecoal or other solid-fuel hopper.

F is the air-blast machine, of any suitable G is an oil tank orreservoir, and H is the source of power.

The burner, as shown in the drawings, is annular or cylindrical orsubstantially cylindrical in shape. The walls arefireproof or ofrefractory material, as the same must retain and withstand intense heat.By refractory material I mean any material which is in herentlysufficiently difiicult of fusion to withstand hightemperatures or whichis rendered difficult of fusionby any of the well known means, as by acirculating coolin fluid. The end of the burner is open, an from theopen end the superheated and burning gases are expelled by the incomingair. The fuel-laden air, as it may be termed, after the admixture ismade in the burner is forcibly blown into the burner in such a way thattheair and fuelparticles are thrown outward against the burner-walls andmove and burn in spiralpaths thereupon. The burner interior-.isintensely hot, and the fuel being held closely upon the same is quicklydecomosed, always before reaching the end of the burner, and'the gas andvapor mixing with the air in the burner causes avort ex or ararefication at the center,which draws back any expansion, and as aresult the flame that emerges from the burner is smokeless. Ex-

cept in the initial heatin of the burner-walls and aside from unavoiable radiation from the furnace-chamber inlwhich the burner is locatednoheat is lost.

Obviously the burner may be double- Q that is, open atboth ends, with amiddle inlet or inlets for and the fuel products; but

formost uses, whether arranged vertically or horizontally, the burnerwill be made with a closed end, as shown in the drawings.

When the burner occupies a horizontal position, I prefer theconstruction shown in the drawings, wherein an annulus 2, of refractorymaterial, closed at one end and open at the other constitutes the burnerproper. This 'annufus 2 is referablyincased b cylinder 3 an ma be a truecylin er or may be choked or ared at its discharge end, according to thenature of the combustible-to be consumed or of the particular duty forwhich the burner is designed. I have illus- .trated the annulus as madeup of blocks or bricks, and in practice I prefer to employ ordinary firebricks, my experiments having proven the same to be enduring. The end ofthe annulus is closed by the hollow head 4, wherein the air is preheatedand which is provided with a central opening 5 to receive the end of thefuel-feeding tube or sleeve'6. The head 4 is attached to the flange 3 ofthe casing 3 and with said casing may be covered with any suitablematerial to prevent the 9 radiation of the heat from the burner. Withinthe head and near its periphery I provide a large number of spiral ortangential air ducts or inlets 7, that lead into the annulus These ductsor inlets 7 are preferably larger 9 at their intake ends 7' than attheir discharge ends 7" and have the effect of compressing the preheatedair which is forced through them, thereby increasing its velocity as itenters the annular space 8 in the inner face of thehead 4. This innerface constitutes the closed end of the annulus, and the metal head isprotected by the fire-brick lining 9,

that is set in the recess of the head. The' 1, and upon whic the annularor cylindrical burner may be rotated by the expenditure of very littlepower. The burner is rotated at a slow speed through the medium of oneof the carrying-pulleys 12, which is arranged upon a shaft 13 and bysuitable gears connected with the driven shaft 16, from which thefuelfeeder is operated.

17 is the small driving-pulley, operated by a belt and which may bereplaced by a small. motor mounted upon the rear or outer truck of theburner.

It will be observed that the fuel-tube does not rotate, but is providedin the same casting or head D with the fuel and air tubes or chutes 18and 19, and which is carried upon the tops of the standards 23 on thetruck 10. The fuel-chute or intake-tube communicates directly with therear end of the fueltube 6, while the air-inlet spoutor tube 19communicates with the annular chamber 24, that a metal surrounds thefuel-tube 6. The feeding-head D is machined off to run against themachined surfaces 4 of the head 4 and is pressed against the same bysprin s in the standards 23. The

inner faeeof sai feeding-head is provided with an annular opening 24,corresponding to the opening 22 in the head 4, whereby the air that isforced through the tube 19 may freely enter the head 4 atall times,although said head 4 is in rotation with the annulus or burner roper.The bearing-faces between the fee ing-head D and the head 4 are proofair at the joint.

vided with annular grooves 26, into whichI force a heav lubricant tolubricate the joint and also pac the same to prevent the escapeintroduced with the air, as in my earlier experiments, is simply ushedthrough the opening at the center 0 the closed end of the .burner and,falling into the bottom thereof, is

picked up by the whirling air and spread upon the inner walls of theburner, to which the fuel adheres until coked.

Various devices may be employed for proient means of introducing oil tothe interior a much higher temperature is reached. This iron, resent inmost fuels.

of the burner. Suitable yalves or slides 49 and 50 are provided in thefuel and air chutes, res ectively, for controlling the supply of fue andan to the burner. The interior of the burner is lined or faced with aglaze or film composed of a metalloid or a composition of metalloids thefusing-pointer temperature "of which is very high, approximating 3,000Fahrenheit and resisting volatilization until is derived from the fueland is com osed of high-proof metalloids, such as su ffate of These,being fuse y the intense heat in the burner, accumulate and spread uponthe walls, constituting a glazing of slag when the burner is inoperation and which is constantly added to from the decomposing fuel incombustion. The percentage of high-proof metalloids present in coalof-various kinds is so high that the lining or film is not onlymaintained at all times, but considerable quantities are thrown off fromthe burner as slag, comprising the metalloids and the ash. Because ofthis highproof glazing or film I am able to employ and easily maintainthe annulus of ordinary reseams The fuel instead of being" Lecting orfeedin the fuel into the burner; m; I prefer the s ort screw or eonveyer28,

fractory fire clay or brick which otherwise would quickly melt down'inthe presence of the great heatcreated by the forced concen tratedcombustion that takes lace within the burner. In burning oils w 'chcontain small percentages of metallic im urities'I find it desirable tointroduce smal quanti ties of sulfate of iron and the like, which be ingquickly fused spread upon and protect the walls of the burner.

While my invention is notconfined to a burner of the detailedconstruct'irm herein shown and described onto a burner of any certainsize or proportion of parts, a statement of typical facts and dimensionswill facilitate the understanding of the principles embodied in and theoperation of the burner. Thus the burner illustrated may bedescribed asbeingsix feet in internal len th, three feet in internal diameter,rotated om three to five times per minute, supplied with air in am levolumes and travellng with a velocity of fiom eight to fifteen thousandfeet a minute, and supplied with fuel in proper proportion to the supplyof air, or vice versa. The

capacity of the burner for producing heat is dependent upon thelimitation imposed by the ability of theannulus to withstand fusion andwithin such limits is dependent upon the su ply of fuel and the velocityof the proper y-proportioned quantity of preheated air that is driveninto the burner for the combustion of the fuel rather than upon thedimensions of the burner. Assumin that the pressure of air was such asto yiel a velocity of eight thousand feet per minute circularly orspirally upon the walls of the burner, a burner of the foregoingdimensions would consume about one ton of broken coal per hour.

The operation in detail is as follows: The open end or mouth of theburner is moved. up to and thrust into a suitable opening in thefire-box or combustion-chamber to be heated. The plate 30., with theconveyer or feedscrew, is then removed from the feeding-head and .asupply of shavings and kindling is thrown into the burner. This isignited, and

then the air-blast is turned into the head and there preheated, afterwhich the air entering the burner through the tangential twyers whirlswith great 'velocit upon the walls of the burner. Centrifuga forceoperates to confine the air upon said walls. ing blast within the burnercauses the kindling to burn furiously, and the burner is quickly broughtto a temperature that will admit of the introduction of more diflicultlycombustible fuel. veyer is then replacedv in the feed-tube, and thecrushed coal or other fuel is let down into said tube. Thereupon thebelt is placed upon the driving-pulley 17, and the burner is set intorotation, likewise the feed-screw or conveyer. Thus the fuel begins tobe automatic- The whirl- The feed-screw orconally fed into the hotburner and falling to the bottom of the burner is instantly caught up bythe strong whirlin blast of air and is thrown forcibly against fhc hotwalls and spread thereon. The velocitv of the whirling currents is suchthat it will cause even large articles of coal to rotate within'thewalls 0 the annulus, the same taking a spiral path toward the open endthereof. This spiral, marked by the progress of an incombustibleparticle, has a great number of convolutions within the burner andbefore it emerges from the end thereof, the same bein due to the factthat the centrifugal force t at is developed by the whirling air exceedsthe crowding force of the incoming air, which would produce longitudinalmovement of the particles within the burner. From the beginning thefinely-divided portion of the fuel will be burned in the burner, and theheat generated thereby and by the original kindling under the forceddraft or blast quickly. raises the refractory walls of the burner to ahigh temperature,- every unit of heat stored therein adding intensity tothe combustion 'within the burner, and vice versa, until the Walls ofthe burner become incandescent and the heat thereof so great that theparticles of fuel striking and traveling thereon or even closelyapproaching the said hot walls in the whirling air-current will bealmost instantly decomposed, the gases thereof being added to theelements of the air, which latter has, obviously, been superheatedbycontact with the hot walls. Ignition takes place almost simultaneouslywith decomposition, and the gases in combustion form a whirling flamethat emerges from the burner at white heat. The burning of a gas-flamewithin the burner would not be sufiicient under ordinary conditions tomaintain the Walls thereof at incandescence; but by whirling the body ofair,

as, and fuel centrifugal force is developed to old the combustibleproducts in close contact with the walls of the burner which receive theinitial and greatest heat of combustion of the particles of fuelthereon, the heat being thus constantlyimparted to the burnerwalls andby them to the fresh roducts entering theburner. The walls 0 the burnerare of comparatively small area and little heat is lost therein. Theannular form of the burner and the spiral ath of the fuel particlestherein insure su .ciently long contact between the fuel and the wallsto produce decomposition and ignition. The whirling of the fuel mixtureuponv the walls of the burner and the flame therefrom tends to cause avacuum and vortex at the center of expansion of the gases within thesame.

.metalloids referred to.

minute quantity of the fine ashes and the Smoke is not thrown off by thefurnace except during the first two or three minutes of the startin ofthe fire. The intensity of the flame of t e burner is regulated by thesu ply of pulverized or broken fuel and by the velocity of the airblast,and the degree of heat that is attainable is ver high. It is preferredthat the burner shal roject into a furnace-s ace or combustion-c amberthatfis larger t an the burner, whereby the velocity of the burnin gasesis reduced after leavin the burner an the pressure thereof also re uced,the effect being to retain the heat in the combustionchamber for alonger time and to perceptibly increase the vacuum or vortex or returncurrent in the burner. As before explained, if the burner has notpreviously been lined with high-proof metalloids or slag it will quicklybecome coated therewith from the fused fuel products. The rotation ofthe burnermay be increased to such an extent as to develop centrifugalforce within the burner to retain the fuel particles and the air uponthe walls thereof; but I prefer to operate the same at a functionnamely,that of constantly bringing the necessarily hotter top of theburnerannulus down to the freshly-admitted fuel, markedly increasing therapidity of the fuel decomposition, the fuel particles adhering to thehot brick until corn l'etely coked. Air is obviously drawn from t ecombustion-chamber by the vortex. When oil is introduced to the burnerat either end thereof, it is drawn to the closed end by the vortex andis pro- IIC jected to the hot walls of the burner, being there burnedwith great rapidity.

It is obvious that solid and fluid fuel may be used simultaneously in myburner. The feed-screw operates at any desired s eed within the capacityof the burner, an the feed-tube 6 is kept full of the pulverized orbroken fuel, always presentin a wall of fuel at the end of the burner. Te wall of fuel thus exposed to the heat of the burner and which protectsthe feed-screw insures .the drying of the fuel practically before itreaches the hot walls of the burner. I am better able, therefore, toburn fuel that contains alarge percentage of water and Wholly avoid thecommon necessity of drying the fuel before feeding it to the burner.

of the matting of the fuel when burned on an ordinary grate and alsobecause of the presence in many of the fuels of elements, aside fromcarbon, which are ordinarily inoombustible.

My process makes it possible to consume many elements and products whichunder resent methods are either deposited in the furnace chamber orfiues or go into the ashes.

In the actual operation of this burner the is so small that for allpractical purposes the combustion maybe termed complete and perfect,every possible unit of heat being extracted from the fuel.

With a given area of refractory material the annulus ofiers the longestpath of travel for the fuel particles, and the annular burner istherefore preferred; but satisfactory burners as distinguished from thefurnace-chamber in which the same are used may be built in other shapesand positions.

It is obvious that many modifications of my invention and the apparatusillustrated herein will readily suggest themselves to one skilled in theart, and I therefore do not'confine my invention to the specific stepsor constructlons herein shown and described.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- 1. The improvement in the art of burning fuel, thatconsists in forming an annulus of air in rapid rotation and havingrelatively slow longitudinal movement, confining said annulus during aportion of its travel, feedng fuel by gravity to the interior of saidannulus and applying heat to the exterior of said annulus to liberatethe gases of the fuel and ignite the same, substantially as described.

2. The improvement in the art of burning fuel, that consists in heatingair and forming an annulus of heated air by the action of centrifugalforce, continuously supplying heated air to said'annulus, therebycausing longitudinal movement thereof, confining said annulus during aportion of its longitudinal movement and feeding fuel by gravity to'theinterior of said annulus within the confining means, substantially asdescribed.

3. The improvement in the art of burning fuel, that consists inpreheating air and forming therefrom an annulus having longitudinalmovement and in rapid rotation, feeding fuel to the interior of saidannulus, confining said annulus during a portion of its travel andquantity of ashes through the medium of the confining means applyingheat to the fuel-laden annulus to liberate and ignite the gases of thefuel, substantially as described.

4. The improvement in the art of burning fuel, that consists inpreheating air and forming therefrom an annulus having longitudinalmovement and in rapid rotation, feeding fuel to the interior of saidannulus, confining said annulus during a portion of its said annulus,thereby creating a vortex,

travel and throu h the medium of the confining means applying heat tothe fuel-laden annulus to liberate and ignite the gases of the fuel, andslowly rotating: said confining means, as and for the purpose set forth.

5. The improvement in the art of burmng fuel, that consists incontinuously heating and rotating a refractory annulus, creating awhirling and longitudinally-movin cblumn of air therein, feeding fuel tosai column within said annulus and therein liberating andigniting thegases of .said fueland discharging the resulting substantially asdescribed.

6. The herein-described improvement in the artof burning fuel, thatconsists in continuously heating and rotatin annulus, lining. theinterior thereof with a rotecting agent, creating a whirling andongitudinally-moving column of air in said annulus, permitting thedischarge thereof at the end of said annulus, and axially feeding fuelinto said annulus, therein admixing the fuel with the air, decom osingthe fuel and igniting the gases thereo and creating a vortex in saidannulus ,substantially as described.

7. The improvement in the art of burning fuel, that consists in creatinga whirling and longitudinally-moving annulus of air, confining the sameduring a portion of its longitudinal travel, creating a return vortexwithin the same, adding fuel to said annulus while confined,continuously storing heat from and applying heat to said annulus whileconfined. to liberate the gases of the fuel and ignite the same, androtatin the confining means, substantially as and or the purposespecified.

8. The improvement in the art of burning fuel, that consists in creatinga hollow cylinder of air, mixing fuel therewith by gravity, igniting thefuel within said cylinder, co ing said cylinder, rapidly rotating saidcylinder of air and causing it to move longitudinally within theconfining means, storing heat from and applying heat to the exterior ofsaid cylinder to continuously liberate and ignite the fuel-gases androtating said confining means, substantially as described.

9. The herein-described process of burning fuel, that consists inforcibly creating a rap idly-rotatin and longitudinally-movin column ofpre eated air, thereafter supp lying fuel to the interior of said columnand mixing the fuel with, the air, meantime confining said column duringa portion of its longitudi-- nal movement, rotatin the confining meansand through the medium thereof continuously storing'heat from andapplying heat to the confined mixtufe of air and fuel and thusliberating and igniting the fuel-gases during the rotation of saidcolumn within said confining means, substantially as described.

10. The improvement in the art of burning fuel, that consists increating a rotating and burning gases from a refractory 'ros IIO

longitudinally-moving annulus of air, suplying fuel to the interior ofsaid annulus and y gravity and centrifugal force adding and admixing thefuel with the air of said annulus, confining the'annulus and applyingheat thereto throughout a given area, there y decomposing the fuel,igniting and burning the gases and creating andmaintaining within saidannulus a vortex that prevents the es-' cape of combustible products,substantially,

as described.

1 1. The improvement in the art of burning fueL'that consists inforcibly creating a spirally-progressing annulus of air, thereafterinteriorly admixing fuel with the air of said annulus, applying heat toa given area thereof, thereby igniting and burning the fuel iproductathe resulting flame being delivered om the area of heatapplication, and a vortex being created with said annulus, substantiallyas described. I

12. The improvement in the art of burning fuel, that consists in formingby centrifugal force a substantial annulus of air mixed with fuel andrarefied at its axis continuously supplying air and fuel at one end ofsaid annulus and thereby imparting longitudinal movement to the annulus,confining said annulus against peripheral expansion during a portion ofits longitudinal travel, afterward permitting the expansion thereof,meantime igniting the combustible constituents of the annulus, causingthe same to burn while con fined and rotating the'co'nfinin'g' means toadvance the freshly-supplied-fuel, substantially as described.

13. The improvement in the art of producing heat from fuel that consistsin establishing a high temperature in a heat-retaining an nulus,rotating said annulus, forcing air tangentially into said-annulus,thereby establishing centrifugal action and a vortex within sa dannulus, feeding fuel into said annulus, causing the combustibles toignite and burn within said annulus and maintain the heat" In witnesswhereof I have hereunto set my hand, this 12th day of January, 1903, atChi cago, Cook county, Illinois.

JOSEPH M. SOHUTZ. In presence of E. G. VREELAND, C. G. HAWLEY.

